Co-axial switch



y 1962 D. H. LANCTOT 3,036,282

CO-AXIAL SWITCH Filed Jan. 18, 1960 FIG. 2 FIG. 3

N VEN TOP DONALD H. LANC'I'OT United States Patent 3,036,282 (IO-AXIALSWITCH Donald H. Lanctot, Malibu, Calif, assignor to Don-LanElectronics, Inc, a corporation of California Filed Jan. 18, 1960, Ser.No. 3,149 1 Claim. (Cl. 333--97) This invention relates generally toco-axial switches and more particularly to an improved switch forconnection in co-axial lines carrying high frequency electromagneticenergy.

Co-axial switches are well-known in the art and find wide use in highfrequency systems. In the design of such switches, it is extremelyimportant that any discontinuities introduced into the co-axial line bythe switching components be minimized to avoid possible reflections orloss of power when the switch is in its on position. On the other hand,when the switch is in its off position it is desirable to maximizeisolation of the disconnected lines.

In many present day applications, co-axial switches are subject torugged environmental conditions particularly when employed in missiles.To insure reliability, it is therefore essential that the switchingcomponents be capa ble of withstanding shocks, vibrations, high gloading, and the like. In addition, filters are sometimes employed forlimiting the frequencies passed to a receiver. The use of such filtersminimizes the possibilities of successful jamming of the signal byunauthorized parties. Filters however, constitute additional componentsin the high frequency system and in cases where weight and space areimportant, it would be advantageous to combine the desired filteringaction with the co-axial switches themselves.

With all of the foregoing in mind, it is a primary object of the presentinvention to provide an improved coaxial switch for connecting anddisconnecting co-axial lines carrying high frequency electro-magneticenergy incorporating the above-noted desirable features.

More particularly, it is an object to provide an improved co-axialswitch which employs moving parts of extremely small mass so that theswitch can withstand normally encountered shocks, vibrations, and high gloading without loss of reliability.

Another object is to provide a co-axial switch in which a straightthrough connection for the inner conductors is elfected when the switchis in the on position whereby minimum power loss occurs across theswitch.

Still another important object is to provide a switch in which only agiven frequency band is passed through the switch when in the onposition to the end that the switch itself serves the dual function ofboth a switch and filter.

Briefly, these and many other objects and advantages of this inventionare attained by providing a conducting body receiving input and outputco-axial connectors in opposite ends, the outer conductors of theconnector being connected through the body and the inner conductorsbeing axially aligned and terminating in opposing contacts within theinterior of the body. A flexible conducting reed is secured at one endto one of the inner contacts and biased laterally so that its free endengages the outer conductor of the other of the contacts. In thisposition, the switch is in its oil condition and the one contact towhich the reed is connected is grounded thereby providing excellentisolation. An actuating means extends laterally into the body betweenthe connectors to engage the reed and is arranged to move into the bodywhen actuated to urge the free end of the reed into contact with theother of the inner conductors to effect the desired straight throughco-axial connection.

The actuating means itself includes a plunger incorporating a conductingportion having a length corresponding to an odd multiple of a quarterwave length of the mean wave length of the electro-magnetic energy. Whenthe actuating means and switch reed are in the on position, one end ofthe conducting portion of the plunger engages the reed and the other endspaced at the odd multiple of a quarter wave length engages the bodyportion of the switch itself so that a. quarter wave stub is provided.Electromagnetic energy of wave lengths different from the quarter wavelength defined by the length of the stub will be attenuated whereaselectro-magnetic energy of proper wave length defined by thedimensioning of the stub, will pass through the switch, the stub itselfappearing as an open circuit.

The plunger may be actuated by electro-magnetic coils so that remoteoperation of the switch can take place. In this case, the conductingportion of the plunger also serves to complete the magnetic circuit withrespect to the coils.

A better understanding of the invention will be had by referring to apreferred embodiment thereof as illustrated in the accompanying drawingsin which:

FIGURE 1 is an overall perspective view of the co-axial switch.

FIGURE 2 is a cross section taken in the direction of the arrows 2-2 ofFIGURE 1 showing the switching components in the oil position; and,

FIGURE 3 is a view similar to FIGURE 2 showing the switching componentsin the on position.

Referring first to FIGURE 1, there are shown co-axial line connections10 and 11 passing into opposite sides of a body member 12. 'Ilhe body 12includes a conducting material which electrically connects the outerconductors of the lines 10 and 11. Within the interior of the body 12there is provided a switch component arranged to be actuated by asuitable mechanism within a housing 13. Remote operation of the switchcan be effected by passing a signal into a pair of leads 14 passing tothe housing 13 as shown. The switch body 12 also includes a mountingbracket 15.

Referring now to FIGURES 2 and 3, it will be noted that the innerconductors of the co-axial lines 10 and 11 terminate in opposed axiallyspaced contact ends 16 and 17 respectively. A flexible conducting reed18 within the body has one end secured as at 19 to the contact 16. Thefree end of the reed 18 in turn is arranged to engage a flat contactingsurface 20 on the other contact 17 when actuated to connect the innerconductors together.

The preferred means for actuating the reed 18 from the open positionshown in FIGURE 2 to the closed or bridging condition shown in FIGURE 3comprises a laterally extending plunger 21 terminating at its upper endin a plate 22 including magnetic material and 'provided with aconducting surface engaging the top cover plate 23 of the housing 13when in the position shown in FIGURE 2. The plunger and top end plate 22are normally held in the position shown by a biasing spring 24. Movementof the plunger is effected by electromagnetic coils 25 surrounding amagnetic core 26 serving as a guide for the plunger itself. The plate 22functions as an armature to complete the magnetic circuit when pulleddownwardly. As shown in FIGURE 2, the electrical conductors 14 connectto the coils 25 so that the same can be energized to operate the switchfrom a remote location.

The flexible reed 18 is biased to the position shown in FIGURE 2 so thatits free end engages the outer condue-tor of the co-axial connection 11as at 27. Thus when the switch is in the off position as shown in FIGURE2, the connection between the inner-conductors is broken and .one of theinner-conductors such as 16 is thetleads 14 to the electro-magneticcoils which pullthe plate 22 downwardly to move the plunger 21 againstthe reed 18. This action will then move the free end of the reed ontothe flat contact surface 20 of the contact end of the inner conductor 17as shown in FIGURE 3. In this position, it will be noted that a straightthrough connection is efiected between the inner conductors wherebydiscontinuities in the geometry of the co-axial lines are minimiZed.-

a When it is desired to open the switch, the signal is removed from theconductors 14- thereby permitting the spring 24 to return the plate 22and plunger to the position shown in FIGURE 2. The resilient nature ofthe reed in turn will then move its free end back to the groundedposition shown in FIGURE 2.

The preferred embodiment of the switch also includes a stub foreitectinga filtering operation when the switch is in its on position. This stubcomprises a conductor v28 disposed within the plunger 21 and having itslower end arranged to make electrical contact with the reed 18 as at 29.The upper end of the plunger 28 in turn electrically connects to the topplate 22. The length of the conducting portion between the point ofcontact 29 and plate 22 is made equal to one quarter of the mean operating wave length of the electro-magnetic energy to be passed by theswitch. a When the switch is in'thefoft position as shown in FIGURE '2,the conductor 28 within everal advantages accrue from the foregoingdescribed construction. As-already' mentioned, the used the flexiblereed enables a straight throughconnection to be effected'when the switchis in the on position so that proper impedan'ce'matching and minimumreflections are realized. In addition, the reed itself is of extremelysmall mass. This'feature coupled with the fact that thefree 7 noted thatthe desired filtering action is accomplished by the plunger structureitself so that the one moving component of the actuating structureserves a dual purpose.

Modifications that fall clearly within the scope and spirit of thisinvention will occur to those skilled in the art. The co-axial switch istherefore not to be thought of as limited to the particular embodimentset forth merely for illustrative purposes.

What is claimed is:

A switch for high frequency electromagnetic energy, comprising: a switchbody having input and output coaxial connectors in opposite ends, theouter conductors of said connectors being axially aligned and connectingto said body and the inner conductors of said connectors being axiallyaligned and terminating within saidbody in opposed spaced contacts; aconducting reed disposed between said connectors and adapted uponmovement to electrically connect said contacts; an actuating meansextending laterally into said body between said connectors, saidactuating means including: a plunger; electro-magnetic coils surroundingsaid plunger, one end of said plunger engaging said conducting reed; anda plate of magnetic material secured to the other end of said plungerfor effecting inward movement thereof uponenergization of said coils-tomove said reed to connect said contacts and effect a'straight-throughco-axial connection, said plunger including a conducting portion inelectrical contact with said reed at one end and said plate at its otherend, said plate having a conducting surface which engages said body whensaid coils are energized and said plate is moved, said conductingportion of said plunger having a length equal to an odd multiple of thequarter wave length of the mean wave length'of said electro-rnagneticenergy, whereby said plunger electrically connects said reed to saidbody when said straight-through co-axial' connection-is effected toprovide a quarter wave length filtering stub.

References Cited in the file of this patent

